JOURNAL OF RESEARCH IN SCIENCE TEACHING VOL. 47, NO. 7, PP. 807–819 (2010) An Investigation of Teacher Impact on Student Inquiry Science Performance Using a Hierarchical Linear Model Ou Lydia Liu, 1 Hee-Sun Lee, 2 Marcia C. Linn 3 1 Educational Testing Service, 666 Rosedale Road, MS 16-R, Princeton, New Jersey 08541 2 Tufts University, Medford, Massachusetts 3 University of California, Berkeley, California Received 29 May 2009; Accepted 20 January 2010 Abstract: Teachers play a central role in inquiry science classrooms. In this study, we investigate how seven teacher variables (i.e., gender, experience, perceived importance of inquiry and traditional teaching, workshop attendance, partner teacher, use of technology) affect student knowledge integration understanding of science topics drawing on previous research. Using a two-level hierarchical linear model, we analyze year-end knowledge integration performance of 4,513 students taught by 40 teachers across five states. Results indicate that students of teachers who value inquiry teaching strategies have significantly higher levels of knowledge integration understanding than those of teachers who believe in traditional teaching methods. In addition, workshop attendance and having a partner teacher teaching the same unit in the same school also have a positive impact on students’ knowledge integration levels. The results underscore the importance of professional development and collegial support in enhancing student success in inquiry science. ß 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 807–819, 2010 Keywords: confirmatory factor analysis; hierarchical linear modeling; inquiry science; knowledge integration; teacher professional development Current reform efforts in science education promote inquiry-based teaching and learning for all elementary and secondary school students (American Association for the Advancement of Science, 2009; National Research Council, 1996, 2007). Successful enactment of inquiry science teaching requires teachers to understand the fundamental concepts in the discipline and to provide thoughtful guidance for students as they grapple with challenging science ideas (Loucks-Horsley, 2003). It is important to identify the teacher variables that can benefit student learning in inquiry science contexts. In this paper, we first review literature on teacher variables that can impact student performance in an inquiry science learning environment. For the context of this research, we describe how the knowledge integration framework (Linn, 2006; Linn & Hsi, 2000) is applied to coordinate curriculum, assessment, and professional development. To investigate the teacher impact on year-end performance of grade 6 to 12 students who studied technology-enhanced inquiry science curriculum units, we first examine how student level variables such as gender, school level, language, and computer use are associated with the student learning outcomes. We then examine how seven teacher-level variables (gender, teaching experience, perceived importance of inquiry and traditional teaching, workshop experience, collegial support, and use of technology) impact learning. The seven variables were chosen on the basis of previous research. Teachers’ Role in Inquiry Science Learning In inquiry learning students formulate driving questions, make predictions, conduct investigations, and communicate science findings. These activities provide students with authentic opportunities to observe, acquire, apply, and consolidate scientific ideas (Lee & Songer, 2003). Ideally, inquiry-based approaches can Correspondence to: O.L. Liu; E-mail: lliu@ets.org DOI 10.1002/tea.20372 Published online 2 April 2010 in Wiley Online Library (wileyonlinelibrary.com). ß 2010 Wiley Periodicals, Inc.